Improving maize carbon and nitrogen metabolic pathways and yield with nitrogen application rate and nitrogen forms

Area of Science:

• Agricultural Science
• Plant Physiology
• Soil Science

Background:

• Excessive nitrogen (N) fertilizer use reduces fertilizer efficiency, a critical issue in agriculture.
• Research often focuses on N application rates, with limited exploration of N forms for improving yield and efficiency.

Purpose of the Study:

• To investigate the impact of varying N application rates and nitrate-to-ammonium ratios on maize post-anthesis carbon (C) and N metabolism.
• To determine the effects of these treatments on maize yield and N-use efficiency under shallow-buried drip irrigation.

Main Methods:

• Two N application rates (210 kg·ha⁻¹ and 300 kg·ha⁻¹) and three nitrate-to-ammonium ratios (2:1, 3:1, 4:1) were applied.
• Measurements included post-anthesis photosynthetic characteristics, key enzyme activities, nonstructural carbohydrate content, N accumulation/transportation, yield, and N-use efficiency.

Main Results:

• The 3:1 nitrate-to-ammonium ratio (NF2) enhanced ear-leaf photosynthetic activity and key C and N metabolic enzyme activities.
• NF2 significantly increased nonstructural carbohydrate accumulation, post-anthesis N accumulation/transportation, and grain yield.
• The lower N application rate (210 kg·ha⁻¹) with the 3:1 ratio showed higher N-use efficiency without compromising yield.

Conclusions:

• An N application rate of 210 kg·ha⁻¹ combined with a 3:1 nitrate-to-ammonium ratio is optimal for high-yield maize production under shallow-buried drip irrigation.
• This approach provides theoretical guidance for efficient N management in maize cultivation.